JP2015102390A - Axle rotation detection pulse counter and tire position determination system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an axle rotation detection pulse counter capable of accurately counting pulses of pulse signals to be output from an axle rotation detection part, and a tire position determination system.SOLUTION: Pulse signals Spl are input in an axle rotation detection pulse counter 23 from axle rotation detection parts 22a-22d provided in respective axles 18a-18d, and these pulse count values are counted. The axle rotation detection pulse counter 23 acquires travel information Ddr through CAN, etc., and counts the pulse count values on the basis of the acquired travel information Ddr when the pulse count values of the respective axles 18a-18d are counted. Specifically, the pulse count values are counted by adding count values when a vehicle 1 travels forward, and subtracting the count values when the vehicle 1 travels backward.

Description

  The present invention relates to an axle rotation detection pulse counting device and a tire position determination system that count output pulses of an axle rotation detection unit.

  Conventionally, as disclosed in Patent Document 1, a tire position determination system (auto-location function) that automatically determines a tire position necessary for air pressure monitoring of each tire is well known. The system of Patent Document 1 includes a first sensor (4a to 4d) provided on a wheel (2a to 2d) and four second sensors (5a to 5d) associated with specific positions in the vehicle. And a measurement system (3) for locating the wheel. The first sensor transmits signals (S4a to S4d) indicating the wheel position to the measurement system. The second sensor measures the angular position of the wheel and outputs the measured values (S5a to S5d). The measurement system determines the phase position (W1a to W3a, W1b to W3b) of the signal of the first sensor related to the measurement value, and the phase position stays within the predetermined allowable range (WTa, WTb) in the predetermined monitoring period. The wheel position is determined by checking whether or not.

Special table 2011-527971 gazette

  In the case of this tire position determination method, a sensor signal (for example, a pulse signal) output from the second sensor is counted to calculate the angular position of the wheel. Regardless of what you did, there was a need to count correctly.

  An object of the present invention is to provide an axle rotation detection pulse counting device and a tire position determination system that can accurately count pulses of a pulse signal output from an axle rotation detection unit.

  An axle rotation detection pulse counting device that solves the above problem is configured such that a pulse signal corresponding to the rotation of the axle is output from an axle rotation detection unit capable of detecting the rotation of the axle, and counts the pulses of the pulse signal. A travel information acquisition unit that acquires travel information that can determine the traveling direction of the vehicle, and a count execution unit that counts the count value by adding and subtracting counts according to the travel information.

  According to this configuration, when counting the pulses of the pulse signal output from the axle rotation detection unit, the count value is added or subtracted based on the traveling information according to the traveling direction of the vehicle. Therefore, even if the vehicle is backed, the count value is counted by calculation according to the vehicle, so that the pulse count value can be counted correctly.

  In the axle rotation detection pulse counting device, it is preferable that the traveling information is information on a tire rotation direction. According to this configuration, since the traveling direction of the vehicle is determined from the information on the rotation direction of the tire, it is possible to accurately determine the traveling direction of the vehicle. Therefore, it is advantageous to accurately count the pulse count value. The tire rotation information is information indicating in which direction the tire is rotating forward or back.

  A tire position determination system that solves the above-mentioned problem is that a tire pressure transmitter attached to each tire transmits a first radio wave associated with at least air pressure data and an ID, and the receiver is provided on the vehicle body. This is a function of a tire pressure monitoring function that receives the first radio wave and monitors the tire pressure of each tire. In the configuration for determining the position of the tire, the tire pressure transmitter is configured such that the tire pressure transmitter is a tire. A specific position detector that can detect that the tire is located at a specific position in the rotation direction and a second radio wave that indicates that the tire is located at the specific position are transmitted from the tire pressure transmitter including at least an ID. A transmission control unit, and the receiver inputs a pulse signal from an axle rotation detection unit capable of detecting the rotation of the axle, and outputs a pulse of the pulse signal. The axle rotation detection pulse counting device includes a travel information acquisition unit that acquires travel information capable of determining the traveling direction of the vehicle, and addition and subtraction of counts according to the travel information. A counting execution unit that counts the count value, and based on the second radio wave received by the receiver, measures the pulse of the pulse signal input from the axle rotation speed detection unit of each axle A plurality of count values calculated for each specific position are acquired, and the receiver associates the ID with the axle by checking which ID is synchronized with which of the count values. And a position determination unit for determining the tire position.

  According to this configuration, when counting the pulses of the pulse signal output from the axle rotation detection unit, the count value is added or subtracted based on the traveling information according to the traveling direction of the vehicle. Therefore, even if the vehicle is backed, the count value is counted by calculation according to the vehicle, so that the pulse count value can be counted correctly. In addition, if the pulse count value can be accurately counted, it is advantageous for more correctly determining the tire position.

  According to the present invention, it is possible to accurately count the pulses of the pulse signal output from the axle rotation detection unit.

The block diagram of the tire position determination system of one Embodiment. Explanatory drawing which shows the component of gravity component force detected with a tire air pressure transmitter. (A), (b) is a communication sequence diagram of a tire pressure transmitter. Explanatory drawing of sampling logic of gravity force. Explanatory drawing of the method of counting a pulse count value. The distribution map of the pulse count value of each wheel in a certain ID. A distribution table of pulse count values plotted for each ID. Formulas for calculating the average and standard deviation.

Hereinafter, an embodiment of an axle rotation detection pulse counting device and a tire position determination system will be described with reference to FIGS.
As shown in FIG. 1, the vehicle 1 includes a tire pressure monitoring system (TPMS) 3 that monitors the air pressure and the like of each tire 2 (2 a to 2 d). In the tire pressure monitoring system 3, a tire pressure transmitter 4 (4a to 4d: also referred to as a tire valve) is attached to each tire 2a to 2d, and at least air pressure data and ID are linked from the tire pressure transmitter 4. The first radio wave (for example, a tire air pressure signal Stp) is transmitted to the vehicle body 5, and the air pressure of the tires 2 a to 2 d is monitored in the vehicle body 5.

  The tire pressure transmitter 4 includes a controller 6 that controls the operation of the tire pressure transmitter 4, a pressure detection unit 7 that detects the tire pressure, a temperature detection unit 8 that detects the temperature of the tire 2, and the tire pressure transmitter 4. Are provided with a gravity detector 9 for detecting the gravity generated in the vehicle, and a transmission antenna 10 that enables radio transmission from the tire pressure transmitter 4. In the memory 11 of the controller 6, a tire ID (valve ID) is written and stored as a unique ID of each tire pressure transmitter 4. The pressure detector 7 is preferably a pressure sensor, for example. The temperature detector 8 is preferably a temperature sensor, for example. The gravity detector 9 is preferably an acceleration sensor (G sensor). The transmission antenna 10 is preferably capable of transmitting a radio wave of, for example, a UHF (Ultra High Frequency) band.

  The vehicle body 5 includes a receiver (hereinafter referred to as a TPMS receiver 12) that monitors the air pressures of the tires 2a to 2d by receiving the tire pressure signals Stp transmitted from the tire pressure transmitters 4a to 4d. The TPMS receiver 12 includes a tire pressure monitoring ECU (Electronic Control Unit) 13 that controls the operation of the TPMS receiver 12 and a receiving antenna 14 that enables radio waves to be received by the TPMS receiver 12. In the memory 15 of the tire pressure monitoring ECU 13, IDs (tire IDs) of the tire pressure transmitters 4 a to 4 d are written and stored in association with tire positions. The TPMS receiver 12 is connected to a display unit 16 installed on, for example, an in-vehicle instrument panel.

  The tire pressure transmitter 4 sends a tire pressure signal Stp from the transmitting antenna 10 at regular or irregular intervals with a predetermined time interval or when the gravity detector 9 detects that the tire 2 has entered a rotating state. Send. For example, the tire pressure signal Stp is preferably a signal including a tire ID, pressure data, temperature data, and the like.

  When the tire pressure signal Stp transmitted from the tire pressure transmitters 4a to 4d is received by the receiving antenna 14, the TPMS receiver 12 checks the tire ID in the tire pressure signal Stp, and if the tire ID check is established, Check the pressure data in the tire pressure signal Stp. If the pressure value is equal to or lower than the low pressure threshold value, the TPMS receiver 12 displays the low pressure tire on the display unit 16 in association with the tire position. The TPMS receiver 12 performs the tire pressure determination for each tire pressure signal Stp received, and monitors the tire pressures of the tires 2a to 2d.

  The TPMS receiver 12 has a tire position determination function (tire position determination system 17) that performs so-called autolocation, which automatically determines which position on the front and rear, left and right of the vehicle body 5 each tire 2a to 2d is attached to. Prepare. The tire position determination system 17 performs the operation of acquiring the rotation amount of each axle 18 (18a to 18d) of the four wheels when the tire pressure transmitters 4a to 4d take a specific position in the tire rotation direction a plurality of times. By checking which of the rotational positions (rotation amounts) of the respective axles 18a to 18d is synchronized with the tire ID, the tire ID and the axles 18a to 18d are associated with each other, and the positions of the tires 2a to 2d are determined. It is preferable that the determination method be used.

  FIG. 2 illustrates a gravity component detected by the gravity detection unit 9. It is preferable that the gravity detector 9 detects a gravity component Gr in the axle direction (tire radial direction) with respect to the gravity G as the gravity applied to the tire pressure transmitter 4. For example, if the centrifugal force is not taken into account, the gravitational component force Gr takes “−1G” or “+ 1G” when it is located at the peak (position “12 o'clock” or “6 o'clock”) in the tire rotation direction. . The detected gravity component Gr may be a tangential component force in the tire rotation direction.

  FIG. 3A illustrates a radio wave transmission sequence of the tire pressure transmitter 4. The tire pressure transmitter 4 preferably takes alternately a first time zone T1 of a short time during which radio waves can be transmitted and a second time zone T2 of a long time during which radio waves are not transmitted. The first time period T1 is preferably “1 second”, for example. The second time period T2 is preferably “30 seconds”, for example. As described above, the tire pressure transmitter 4 repeats the operation of transmitting radio waves during a limited time of 1 second with an interval of about 30 seconds.

  As shown in FIG. 1, the tire pressure transmitter 4 has a specific position detector 19 that can detect that the tire pressure transmitter 4 is positioned at a specific position in the tire rotation direction, and that the tire 2 is positioned at a specific position. It is preferable to include a transmission control unit 20 that transmits a second radio wave (for example, an ID radio wave Spi) that can be transmitted from the tire pressure transmitter 4 by including at least an ID (tire ID). The specific position detector 19 and the transmission controller 20 are preferably provided in the controller 6, for example. The specific position is preferably a peak position in the tire rotation direction, for example. The detection of the peak position is preferably performed a plurality of times. The transmission of the ID radio wave Spi is preferably executed a plurality of times, for example, according to the number of detections of the peak position. The ID radio wave Spi is transmitted during a first time period T1 that the tire pressure transmitter 4 periodically takes.

  The tire pressure transmitter 4 preferably includes an information holding unit 21 that holds one or more specific position information Dtm indicating when the tire pressure transmitter 4 has taken a specific position in the second time period T2. This is because, for example, when the vehicle 1 travels at a low speed and the tire 2 rotates slowly, there may occur a situation in which the peak cannot be detected a predetermined number of times during the short first time period T1, so that the peak occurs in the second time period T2 where radio waves are not transmitted This is because the position is detected in advance. In addition, for example, if radio waves are transmitted at a certain tire angle, when this point becomes null, it will continue to be affected by the null in a fixed manner. In the case of the method of this example, since radio waves are transmitted at an arbitrary tire angle, there is no fixed influence of null. That is, there is also an advantage of preventing the risk that the reception rate of the TPMS receiver 12 is significantly lowered in the determination of the tire position.

  The specific position information Dtm is preferably peak information that can determine when the tire pressure transmitter 4 has taken the peak position. For example, the specific position information Dtm is preferably constructed from the number of gravity sampling points indicating how many times gravity sampling is performed in actual gravity sampling, the gravity sampling interval time which is the execution interval of gravity sampling, and the like.

  As shown in FIG. 3B, it is preferable that the information holding unit 21 detects a peak of a predetermined number of times (for example, 8 times) in a predetermined time zone that goes back from the start point T1a of the first time zone T1. . In the first time zone T1 in which radio wave transmission is possible, the transmission control unit 20 sets one or more pieces of specific position information Dtm held so far together with IDs (tire IDs) for the number of specific position information Dtm. It is preferable to transmit as two radio waves (ID radio wave Spi). At this time, the transmission control unit 20 may transmit these ID radio waves Spi continuously (transmission interval: 10 ms) so as to finish transmitting the ID radio waves Spi for one packet during the first time period T1.

  As shown in FIG. 1, the tire position determination system 17 receives a pulse signal Spl from the axle rotation detection unit 22 (22a to 22d) of each axle 18a to 18d, and counts the pulses of the pulse signal Spl. A pulse counting device 23 is provided. The axle rotation detection pulse counting device 23 is preferably provided in the tire pressure monitoring ECU 13, for example.

  The axle rotation detection units 22a to 22d are preferably ABS (Antilock Brake System) sensors provided on the axles 18a to 18d. In this case, the axle rotation detection units 22a to 22d detect, for example, a plurality of (for example, 48) teeth provided on the respective axles 18a to 18d by the sensing unit on the vehicle body 5 side, thereby generating the rectangular wave pulse signal Spl. Output to the TPMS receiver 12. The axle shaft rotation detection pulse counting device 23 detects 96 pulses (count value: 0 to 95) per tire rotation if both the rising edge and falling edge of the input pulse signal Spl are detected.

  The axle rotation detection pulse counting device 23 performs a count value (by adding and subtracting counts according to the travel information Ddr, and a travel information acquisition unit 24 that acquires travel information Ddr that can determine the traveling direction of the vehicle 1. A pulse count value) Dc. The travel information acquisition unit 24 and the count execution unit 25 are preferably provided in the tire air pressure monitoring ECU 13, for example.

  The travel information acquisition unit 24 preferably acquires the travel information Ddr through a CAN (Controller Area Network) or LIN (Local Interconnect Network) in the vehicle, for example. The travel information Ddr is preferably information on the rotation direction of the tire 2, for example. In this case, for example, depending on the type of the axle rotation detection unit (ABS sensor) 22, the axle rotation detection unit 22 outputs information on the rotation direction of the tire 2, so this information is obtained from the axle rotation detection unit 22. Thus, it is possible to acquire information on the rotation direction of the tire 2. Further, the travel information Ddr may be information on the operation position (shift position) of the shift lever, for example. In this case, the travel information acquisition unit 24 acquires information on the operation position of the shift lever from the shift ECU, for example.

  The count execution unit 25 adds a pulse count value Dc when determining forward based on the travel information Ddr, and subtracts the pulse count value Dc when determining back based on the travel information Ddr. The numerical value Dc is measured. The count execution unit 25 executes this pulse count for each of the axles 18a to 18d.

  The TPMS receiver 12 includes a position determination unit 26 that associates ID1 to ID4 and the axles 18a to 18d to determine the tire position by confirming which ID is synchronized with which of the count values Dc. . The position determination unit 26 is preferably provided, for example, in the tire air pressure monitoring ECU 13. For example, the position determination unit 26 calculates the distribution of the pulse count value Dc for each ID (tire ID) by taking the statistics of the pulse count value Dc for each ID (tire ID), and ID1 to ID1 based on this distribution. It is preferable to determine the tire position by confirming the synchronization between ID4 and the axles 18a to 18d. The distribution is preferably “variation”, “average deviation”, “standard deviation”, or the like. When peak detection is performed in advance in the second time period T2, the position determination unit 26 calculates the pulse count value Dc for each specific position from the received specific position information Dtm, and determines the tire position from this reverse calculation value. It is preferable.

Next, the operations of the tire position determination system 17 and the axle rotation detection pulse counting device 23 will be described with reference to FIGS.
As shown in FIG. 4, the tire pressure transmitter 4 reads the gravitational component force Gr and confirms the gravity waveform at a second time period T2 in which radio waves are not transmitted, a predetermined time before starting peak detection. The gravity sampling interval time Ta having a longer time corresponding to the read gravity component Gr is set. Then, the tire pressure transmitter 4 starts pre-gravity sampling for detecting the gravitational component force Gr at the gravity sampling interval time Ta.

  At the time of pre-gravity sampling, the tire pressure transmitter 4 first monitors where the peak of the gravity component force Gr occurs in the gravity sampling performed at the gravity sampling interval time Ta. When the tire pressure transmitter 4 detects the peak of the gravity component Gr, the tire pressure transmitter 4 again monitors the peak of the gravity component Gr in order to measure one period of the pre-gravity sampling. When the tire air pressure transmitter 4 detects the peak of the gravitational force Gr again, it calculates the pre-gravity sampling period based on the time between the previous peak and the subsequent peak. Then, the tire pressure transmitter 4 sets Tb corresponding to the period of the pre-gravity sampling as a gravity sampling interval time used in actual gravity sampling. That is, since the number of times of gravity sampling per rotation of the tire is determined by a specified value (for example, 12 times), the optimum gravity sampling interval time Tb is set so that the number of times of gravity sampling takes the specified value during actual gravity sampling. The

  The tire pressure transmitter 4 performs actual gravity sampling at the gravity sampling interval time Tb. That is, the tire pressure transmitter 4 repeatedly detects the gravitational component force Gr at the gravity sampling interval time Tb, and detects a plurality of peak positions necessary for determining the tire position. In the case of this example, one cycle of actual gravity sampling is set to Tr including a predetermined number (for example, 12 times) of the gravity sampling interval time Tb.

  When the information holding unit 21 detects the peak position in the gravity sampling repeatedly executed at the gravity sampling interval time Tb, the information holding unit 21 stores the specific position information Dtm in the memory 11. Thereafter, the information holding unit 21 holds the specific position information Dtm in the memory 11 every time a peak is detected.

  As shown in FIG. 3, the transmission control unit 20 sets the specific position information Dtm held in the memory 11 to the number of the specific position information Dtm when the first time zone T1 in which radio wave transmission is possible. An ID radio wave Spi is transmitted from the transmission antenna 10 together with the ID. The ID radio wave Spi is a signal including at least a tire ID and specific position information Dtm. Specifically, the ID radio wave Spi may be a signal including each information of the tire ID, the number of gravity sampling points, and the gravity sampling interval time Tb. The ID radio wave Spi is preferably transmitted continuously at a short interval of, for example, about 100 ms so that it can be transmitted during the first time period T1.

  As shown in FIG. 5, the axle rotation detection pulse counting device 23 sequentially calculates a pulse count value Dc for each of the axles 18 a to 18 d based on output pulses from the axle rotation detection units 22 a to 22 d. The axle shaft rotation detection pulse counting device 23 may calculate the current pulse count value Dc by calculating the pulse count value Dc every predetermined time interval (for example, 20 ms) and sequentially integrating the pulse count value Dc. In this example, since the pulse output is modulo 95, the pulse count value Dc repeats from 0 to 95 every time the tire 2 makes one revolution.

  In counting the pulse count value Dc, the travel information acquisition unit 24 acquires the travel information Ddr through, for example, CAN or LIN, and notifies the count execution unit 25 of this. The count execution unit 25 counts the pulse count value Dc for each of the axles 18a to 18d by performing an addition process when the vehicle 1 moves forward and performing a subtraction process when the vehicle 1 moves back. Specifically, at the update timing of a certain pulse count value Dc, if the difference between the pulse count value Dc at the current timing and the pulse count value Dc at the previous timing is taken and the vehicle 1 moves forward, If this difference is added and the vehicle 1 is back, the pulse count value Dc is updated by subtracting this difference. Then, this process is repeated for each update timing of the pulse count value Dc to measure the pulse count value Dc.

  As illustrated in FIG. 6, the position determination unit 26 acquires the pulse count value Dc of each axle rotation detection unit 22a to 22d every time the ID radio wave Spi is received. In the case of this example, the pulse count value Dc is calculated backward from the specific position information Dtm, and the reverse calculation value is calculated for each specific position information Dtm. And the position determination part 26 takes the statistics of these back calculation values, and adds each statistic every time it receives each ID radio wave Spi of a packet unit, and determines a tire position. That is, as shown in the figure, the distribution of the first packet is calculated, and if the tire position is not fixed at the first packet, the distribution of the second packet is added to the first packet and the tire position is determined. The same processing is repeated after the third packet, and the distribution is updated, and the tire position is determined from this distribution.

  FIG. 7 illustrates a specific example of tire position determination. The position determination unit 26 creates a distribution table 27 as shown in FIG. The position determination unit 26 performs absolute evaluation for determining the legitimacy of the distribution independently for each pulse count value Dc and relative evaluation for determining the legitimacy of the distribution among the plurality of pulse count values Dc. It is preferable to determine the tire position based on the result. Relative evaluation is an index for judging whether the own wheel is compared with the other wheel and is sufficiently synchronized with the other wheel. In this example, “average of deviation” and “standard deviation” are given as examples of distribution. The average deviation and standard deviation are smaller as the determination result is better.

  As shown in FIG. 8, the average deviation is the same when the pulse count value is “x”, the total number of collected pulse count values is “n”, and the average of the collected pulse count values is “x ′”. It is calculated from the equation (α) in the figure. The standard deviation is calculated from the equation (β) in the figure. Hereinafter, “average deviation” and “standard deviation” are collectively referred to as “bias value”. The absolute evaluation is an evaluation for determining whether or not the bias value falls below a threshold value. Relative evaluation calculates the difference between the deviation value of the own wheel and the deviation value of the other wheel, and whether or not this difference is equal to or greater than the threshold, that is, the deviation value of the absolute evaluation of the own wheel is sufficiently larger than that of the other wheel It is evaluation which determines whether it is small. The position determination unit 26 determines that the axle 18 and the tire 2 are synchronized with each other if the bias value is equal to or smaller than the threshold value in the absolute evaluation and the difference between the bias values is equal to or larger than the threshold value in the relative evaluation. .

  In the case of the example of FIG. 7, the pulse count values of the left front axle 18b in ID1 are collected in the vicinity of “20”, so that the bias value of the left front axle 18b in ID1 is within the threshold value, To do. On the other hand, in ID1, since each pulse count value of the right front axle 18a, the right rear axle 18c, and the left rear axle 18d takes a value that does not converge to one value, these bias values take bad values. For this reason, the difference between the deviation value of the left front axle 18b in ID1 and that of the other axle is equal to or greater than the threshold value, so the relative evaluation is also satisfied. Therefore, since it can be confirmed that ID1 is synchronized with the left front axle 18b, these are linked and it is determined that ID1 is the left front tire 2b. Similarly, the tire positions are also determined in ID2 to ID4.

  If the position determination unit 26 cannot determine the positions of all four wheels in one determination, the position determination unit 26 determines the positions of the remaining wheels by the same process. Then, the same processing is repeated until the positions are determined for all four wheels. When the position determination for all four wheels is completed, the position determination unit 26 writes the determination result in the memory 15 and updates the tire position. The tire position determination process may be executed each time the ignition switch of the vehicle 1 is turned on, for example.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) When counting the pulses of the pulse signal Spl output from the axle rotation detector 22, the count value is added or subtracted based on the travel information Ddr according to the traveling direction of the vehicle 1. Therefore, even if the vehicle 1 goes back, the pulse count value Dc is counted by calculation according to the vehicle 1, so that the pulse count value Dc can be correctly counted.

  (2) When the traveling information Ddr is information on the rotation direction of the tire 2, the traveling direction of the vehicle 1 can be accurately recognized. That is, when the travel information Ddr is information on the shift position, it is not possible to identify whether the vehicle 1 is traveling forward or back when the “N position”, but the travel information Ddr is the rotation of the tire 2. If it is direction information, it can be identified. Therefore, it is advantageous to accurately count the pulse count value Dc.

  (3) The tire position determination system 17 transmits tire IDs 1 to ID4 received by the TPMS receiver 12 by causing each tire pressure transmitter 4 to transmit an ID radio wave Spi indicating when the tire pressure transmitter 4 has taken a specific position. However, the tire position is determined by confirming which of the axles 18a to 18d is synchronized. Therefore, the tire position can be determined without providing an initiator for each of the tires 2a to 2d. Further, in this tire position determination method, if the pulse count value Dc of each axle 18a to 18d can be accurately counted, this is advantageous for more correctly determining the tire position.

Note that the embodiment is not limited to the configuration described so far, and may be modified as follows.
The specific position information Dtm collected during the second time zone T2 may be transmitted all at once at the time of the first radio wave transmission when the first time zone T1 arrives.

As the specific position information Dtm, various kinds of information such as the time when the peak position is detected or the time traced back from the start point T1a of the first time zone can be adopted.
The specific position is not limited to the peak position, and may be a predetermined position taken by the tire pressure transmitter 4 in the tire rotation direction.

The axle rotation detection unit 22 may output a pulse count value detected during a certain time interval to the TPMS receiver 12 as count data.
The axle rotation detection unit 22 is not limited to an ABS sensor, and may be any member that can detect the rotational position of the axle 18.

The axle rotation detection unit 22 may transmit a detection signal to the TPMS receiver 12 wirelessly.
The pulse count value Dc is not limited to the pulse count value, and can be changed to another parameter as long as it is similar to the rotational position of the axle 18.

The weighting method can be appropriately changed to various modes.
The tire pressure transmitter 4 is not limited to detecting the peak in advance in the second time zone T2 when the radio wave transmission is not performed, but the ID is detected at the peak detection timing in the first time zone T1 in which the radio wave transmission is possible. It may be one that transmits a radio wave Spi.

The tire pressure transmitter 4 may periodically transmit the ID radio wave Spi.
The tire position determination method is not limited to the method of determining the position by taking the distribution of the pulse count values Dc of the axles 18a to 18d for each ID as described in the embodiment. For example, the tire position may be determined by taking an average of the pulse count values Dc of the respective axles 18a to 18d for each ID and confirming which of the average values the ID is synchronized with. Thus, the tire position determination method can be appropriately changed to various modes.

The first radio wave and the second radio wave may be the same radio wave.
The distribution is not limited to variation, average deviation, and standard deviation, and can be changed to other parameters as long as the synchronization between the tire ID and the axle 18 can be determined.

The travel information Ddr can be changed to various information as long as the traveling direction of the vehicle 1 can be determined.
The axle rotation detection pulse counting device 23 is not limited to being applied to the tire position determination system 17 and can be appropriately employed in other systems.

Next, technical ideas that can be grasped from the above-described embodiment and other examples will be described below together with their effects.
(A) In the tire position determination system, the position determination unit calculates a distribution of axle rotation information of each axle for each ID by taking statistics of the axle rotation information for each ID, and calculates the distribution. It is preferable to determine the tire position by confirming the synchronization of the ID and axle based on the basis. According to this configuration, since the tire position is determined by handling each piece of axle rotation information as individual data, a large amount of data necessary for determining the tire position can be collected in a short time. This is advantageous in that the time required for tire position determination can be shortened. Therefore, it is possible to determine the tire position more correctly in a short time.

  (B) In the tire position determination system, the tire pressure transmitter includes an information holding unit that holds the specific position detected in advance in a time zone in which the tire pressure transmitter cannot transmit radio waves, The transmission control unit transmits the held information on the specific position as the second radio wave when the tire pressure transmitter is in a time zone in which radio wave transmission is possible. According to this configuration, it is advantageous to obtain information on a plurality of specific positions necessary for determining the tire position without being insufficient.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 (2a-2d) ... Tire, 3 ... Tire pressure monitoring system (tire pressure monitoring function), 4 (4a-4d) ... Tire pressure transmitter, 5 ... Vehicle body, 12 ... Receiver (TPMS receiver) ), 17 ... Tire position determination system, 18 (18a-18d) ... Axle, 19 ... Specific position detection unit, 20 ... Transmission control unit, 22 (22a-22d) ... Axle rotation detection unit, 23 ... Axle rotation detection pulse count Device: 24 ... Travel information acquisition unit, 25 ... Count execution unit, 26 ... Position determination unit, Spl ... Pulse signal, Dc ... Pulse count value, Ddr ... Travel information, Stp ... Tire pressure signal as an example of the first radio wave, Spi: ID radio wave that is an example of the second radio wave.

Claims (3)

From the axle rotation detection unit capable of detecting the rotation of the axle, a pulse signal corresponding to the rotation of the axle is output, and in the axle rotation detection pulse counting device for counting the pulses of the pulse signal,
A travel information acquisition unit that acquires travel information capable of determining the traveling direction of the vehicle;
An axle rotation detection pulse counting device, comprising: a count execution unit that counts the count value by adding and subtracting a count in accordance with the travel information. 2. The axle rotation detection pulse counting apparatus according to claim 1, wherein the travel information is information on a tire rotation direction. Each tire tire receives a first radio wave associated with at least air pressure data and an ID from a tire pressure transmitter attached to each tire and receives the first radio wave with a receiver provided on the vehicle body. 1 function of a tire air pressure monitoring function for monitoring air pressure, in a tire position determination system for determining the position of the tire,
The tire pressure transmitter has a specific position detector that can detect that the tire pressure transmitter is located at a specific position in the tire rotation direction, and a second radio wave that indicates that the tire is located at the specific position. A transmission control unit including at least an ID and transmitting from the tire pressure transmitter;
The receiver includes an axle rotation detection pulse counting device that inputs a pulse signal from an axle rotation detection unit capable of detecting the rotation of the axle and counts the pulses of the pulse signal,
The axle rotation detection pulse counting device counts the count value by adding and subtracting a count according to a travel information acquisition unit that acquires travel information capable of determining the traveling direction of the vehicle, and the travel information. A counting execution unit, and based on the second radio wave received by the receiver, a count value calculated by measuring a pulse of a pulse signal input from an axle rotation speed detection unit of each axle Get multiple for each position,
The receiver includes a position determination unit that checks which ID is synchronized with which of the count values, and determines the tire position by associating the ID and the axle. Tire position determination system.